1. Technical Field
The present invention relates to printed circuit boards, and more particularly relates to an inner substrate for manufacturing multilayer printed circuit boards and a method for manufacturing multilayer printed circuit boards using the inner substrate.
2. Description of Related Art
In order to accommodate development of miniaturization and multifunction of electronic products, multilayer printed circuit boards are widely used due to their characteristics such as micromation, light quality, high-density interconnection.
Multilayer printed circuit boards usually includes multilayer rigid printed circuit boards and multilayer flexible printed circuit boards. Nowadays, multilayer printed circuit boards are manufactured using a typical sheet-by-sheet process. However, only one multilayer printed circuit board can be manufactured at a time, using the typical method describe above. Thus, efficiency of manufacturing multilayer printed circuit boards is low and cost of manufacturing multilayer printed circuit boards is high.
Currently, flexible printed boards can be manufactured using a roll-to-roll process that is a substitute of a typical sheet-by-sheet process. The roll-to-roll process can enhance efficiency of manufacturing flexible printed boards. However, a multilayer flexible printed circuit board is generally thicker than a single layer flexible printed circuit board, flexibility of the multilayer flexible printed circuit board is low. Thus, it is difficult for the multilayer flexible printed circuit board to be wrapped around a roller. Therefore, the roll-to-roll process for manufacturing the single flexible printed circuit board is not suitable for manufacturing the multilayer flexible printed circuit board. Therefore, multilayer flexible printed circuit boards are still manufactured using the sheet-by-sheet process like typical multilayer rigid printed circuit boards. Thus, efficiency of manufacturing multilayer flexible printed circuit boards is also low and cost of manufacturing multilayer flexible printed circuit boards is also high.
What is needed, therefore, is an inner substrate for manufacturing multilayer printed circuit boards and a method for manufacturing multilayer printed circuit boards using the inner substrate, thereby improving efficiency of manufacturing multilayer printed circuit boards.